Electrical surge recorder



Jan. 9, 1951 Filed Jan. l5,

P05/Tl VE F/GURE J. H. WAGHORNE ELECTRICAL SURGE RECORDER 2 Sheets-Sheetl Jan. 9, 1951 J. H. wAGHoRNE 2,537,384

ELECTRICAL SURGE RECORDER Filed Jan. 15, 1948 2 Sheets-Sheet 2 o 5 l0 l5zo 25 3o 35 40 SUI-mg penn 1N H/Lovours am Patented Jan. 9, 1951 UNITEDSTATES PATENT OFFICE ELECTRICAL SURGE RECORDER John Henry Waghorne,Toronto, Ontario, Canada Application January 15, 1948, Serial No. 2,484In Canada June 10, 1947 -the electrostatic photo-sensitive type, inwhich a record of the characteristics vof a surge is obtained throughthe instrumentality of aconduct- Ying electrode in engagement with aphoto-sensitive surface, thereby producing so-calledLichtenbergAfigures.

It is a main object of this invention to provide a device of thischaracter having a light-proof` and weather-proof casing for containingthe sheet of sensitized material on which the surge is to be recorded,the casing being so constructed that it may be readily dismantled topermit the lm of4 sensitized material to be replaced.

It is another object of this invention to` provide a surge recorderwhich may be coupled to high voltage lines or other electrical devicesby connecting it on the line-side ofthe capacitance voltage divider.

, mechanically movable element, having appreciable inertia, may be madeto sensibly record. y Such a, surge may be caused in electrical circuitsby... various agencies, such as lightning, grounds of exceedingly shortduration and other causes,

and may adversely affect the operation of the circuit in accordance withthe steepness, duration, amplitude and polarity thereof. It is thereforehighly desirable that observation of these characteristics be obtainedfrom an instrument that shall be easy to operate and that shall other-.wise be adapted as a standard electrical instrughment.

1 1@Apparatus of this nature for recording electrical: surges was iirstdisclosed in an article entitled ..The- Klydonograph by J. F. Peterswhich ap- ,peared in Electrical Worldon April 10th, 1924.

graphic development. The pattern has a characteristic design if thevoltage is positive, and a `different characteristic design if .thevoltage is negative. The diameter of the pattern is a funci 5 tion ofthe peak value of the voltage applied and hence, through propercalibrati-on, the pattern can be used to measure the value of an appliedvoltage. Y

- For a more complete description of the operat- Y Ving principles of`such devices, reference is made to the aforesaid article by J. F.Peters and also to U. S. Patent No. 1,649,180 dated November th, 1927.Several improvements have since been made in this method of surgerecording, including `15 the recording of botha positive and negativefig- Y Yure regardless of the actual surge 'polarity by us- 'ing'zadouble film unit, as disclosed in U. S. Patent .No. 1,702,412 dated4February 19th, 1929. l

There have similarly been many methods of coupling surgeprecorders tohigh voltage lines and other electrical devices in order to supply nreduced voltage to the recording units. Various 'arrangements of rings,bars and insulator strings have been used to provide the capacitances toproduce a voltage divider. However, they have all been large more orless permanent installations which are relatively expensive, and thesefrequently couple in some degree to other phases or circuits as well asto the one desired.

All of the foregoing and still further objects and advantages of theinvention will become apparent from a study of the followingspecification, taken in conjunction with the accompanying drawings,wherein like characters of reference designate corresponding partsthroughout' 'the several views, and wherein:

Figure l is a view partly in elevation and partly in verticalcross-section of a completely assem- .bled surge recorder constructed inaccordance 40 with. this invention and shown connected to a .power line,

'Figure 2 .is a perspective view of the said surge recorder,

Figure 3 is an exploded perspective view of the recording unit, y

Figure .4. is achart illustrating the directcalibration ofatypicaLrecording unit constructed K 'with the rods 3l and 4.

tween the peripheriesfoi the dishes.,

Figure 5 is a chart illustrating the calibration of the combinedrecording and coupling units with sensitivity control extensions ofthree dfferent lengths, and

Figure 6 is a chart illustrating the potential distribution between aconductor and ground plane.

Referring particularly to Figures l and 3, the recording unit comprisestwo' concave dishes. I and 2 made of electrically non-conductingmaterial disposed with their peripheries abutting one, another toprovide a hollow shell. said dishes extend threaded rods 31'and- 4'respectively, the said rods being secured to the respective dishes byoopoitely facing pairs of locking nuts 5 and 6.

Through the I carrying the surge.

4 Thus resistor 29 may be connected between hood 2i! and rod 4.

` Remarks vlneutral plane is established through the center of the unit.Thus, the recording is similar to Films of electrically conducting paint'I and B are painted on a portionofithe..

inside surfaces of dishes I and 2 respectivelyso, as to be electricallyinsulated from one another,

and these are respectively in electrical contact The inner end ofy eachrod is hollowed4 out, and

Vinsertedtherein are spring-pressed pins 9 and t0; Coiled around the.rod-s are( hel-ical springs l l .and f2 respectively,l one end of thesaid springs y' of the rod in which'i't is inserted. The` spring isvtherefore in tension when it is attempted to force the, pin inside, itsrod, and` therefore each assembly of rod, pin and tension springprovides. a .spring-pressed electrode.

The hollow shell provided bythe two concave dishes, with,theirperipheri'es abutting one `another is. divided by a` flat partitionof. electrically non-conducting. material,` [31 which is gripped'besensitized films 1.4 and lare disposed on opposite faces of t0 are inintimate contact therewith.. If desired, the nlm may be in sheets cutton dimensions. such that portions thereof` may be gripped between theperipheries of the dishes. A'rubber v'band .i67 securely closes theassembly and makes it light-proof and weatherproof- The coupling unit`comprisesy an aluminum hood 20 through the center of which extends abushing 2| provided with internal. threads 22; An

,aluminumhinged hanger 23 is. secured to the hood by means of thebushing 2| extending; therethrough the nut 24. which is screwed on the.said bushing. At thel opposite end of the hanger a hoolr 2.5 providedwith a screw clamp 26 whereby the device.. may be secured to a powerline 21 or other power device wherein. the surge Ais toy be. measured.

An extension 28 issecured to the'outer: end. of

.frod 4L,- The length of the extension 28 which s used is determined bythe operating voltage of fthe: equipment;- undery test; withdifferentlengths of extensions diierent voltage ranges maybe re.'-

cordect It is'usualto choose an. extensionof a length such that it willrecord voltagesgreater than twice the', normal line voltage, as. surgesvbelow this value are not of interest'. Y With high operating voltages adark; spot may under somey conditions beproduced on the sensi:-

Vtizedlrns4 even'4 when no .surges have occurred.

. `40 theV partition, and the spring-pressed pins 9 and when it ismounted closely to the line.

that inv a unit with a ground plane, except that twiceA the voltage.. isrequired to produce the same sized' figures.' 1n Figure 4 is shown adirect calibration of a typical recording unit constructed in accordancewith this invention, for both posiytive .and negative Lichtenbergfigures using a 11/2 x 40 microsecond weave. To obtain this cali-.brat/fion, voltage surgesfof various known magnitudes. are applied-J'between the "terminals of the recording unit (therecording unit oicourse hav- 'ing tobe reloaded with fresh sensitized'iilrn'after i eachvoltage surge), andafter the films are developed'the radii ofthe'patterns produced are plottedagainstthe known applied voltages, asshown in Fig. 4.' n i l Heretoforefsurge recorders have been' coupled tohigh voltage 'lines and other electrical devices with the recordingunity at the grounded end; this has required 4a small'electrostaticcapacitance irom the unit to the line compared to the capaci- 'tancefrom the lijve terminal of the unit to ground ror neutral plane. Inaccordance with this invention, the unit is coupled' on the line sideof` the capacitance divider therebyreversing this condition ofoperation.'v This makes the recorder practically independent of locationwith respect to other circuits and" to ground because the'. volt'- agedistributionin the neighbourhood' of acon- `ductor is relativelyindependent of the location of the ground planefor grounded objectsvwhen the spaoing'be'tween the two is greater than about 5feet. For aconductor of radius' 0.04 feetv ('one inch difameterlnthe voltagedistribution isfsho'wn in Figure 6', for values of conductor height of`5feet land 20 feet above the reference plane. It will be seen from thesecurves that wide variations in the height of the; conductor above thereference plane -will'have negligible effect upon the voltage adjacentthe conductor, provided the conductor is at a height greater than 5 feetvfrom ground. vThe hood '20 will 'not materiallyv affect the voltagedistribution as given in these curves (Figure 6) 4 The hood is notintended'to be nor is it a corona shield; it

is an electrostatic shield, whose function is to control andreduce theeffectiveelectrical distance of rod ll' from the line, thereby allowingyuse makes the recording practically independent of variations inproximity of vother lines" ror of y'grounded objects.

Figure 5 shows the calibrations for thefrecording and couplingunitscoinbined, using three different-sizes;v of sensitivity-controlextension 28.

A 1% x40` microsecond wave was used for these .calibrationsA Itwill bevnoted that the concave downward curvature seen in these curves is notpresent in the calibration curve of the. recording vunitperse shown inFigure 4; this cannot be dentely. accounted,or, Vbut; ionization.,around f I It is thought the edge' of the hood at the' higher voltages"may be' a possible explanation of this variation.'

. The surge recorder disclosed -herein may be in- Ystalled'andfremovedfrom the live highvoltage linesor'electrical devices by means ofatreated 1 l.wooden stick having a head designed to engage clamp`26.

that the construction anduse of the invention will be apparent from theabove description of the various parts and their purpose. It is to beunderstood that the form of my invention herewith shown and described,is to be taken as a preferred example of the same, and that variouschanges in the shape, size and arrangement of parts may be resorted to,without departing from the spirit of my invention or the scope of thesubjoined claims.

What I claim as my invention is:

l. A surge recorder of the electrostatic photosensitive type forelectrical apparatus, comprising a hollow non-conducting member havingspaced walls disposed opposite to each other, an electricallynon-conducting partition therebetween, a lm of sensitized material onone side of the partition, a rod-type electrode secured to one of thesaid walls and having one end in contact with the film, another rod-typeelectrode secured to the other wall in substantial alignment with therst mentioned electrode and having one end adjacent to the other side ofthe partition, the other end of one of the said electrodes being adaptedto be directly connected to the electrical apparatus in which a surge tobe recorded passes, the other` end of the other of the said electrodesbeing adapted to be electrostatically coupled to ground, and anelectrically conducting electrostatic shield connected to the electrodewhich is adapted to be connected to the electrical apparatus, the saidshield extending around the hollow member and being spaced from i yeriesabutting one another to provide a hollow shell, a film of electricallyconducting material on a face of each dish, the said films being spacedand insulated from one another, a partition of electricallynon-conducting material adapted to divide the hollow shell at theabutting peripheries, a film of sensitized material on at least one faceof the partition, a pair of` rod-type electrodes disposed normal to thedishes in substantial alignment with each other and having theiradjacent ends spaced apart by the partition, each of the said electrodeshaving an outer end extending through one of the dishes, and being inelectrical contact with the film of electrically conducting material ona face of the dish through which it extends, means for electrically`connecting the outer end of one of the electrodes to the electricalapparatus in which a surge to be recorded passes, and .means forgrounding the outer end of the other electrode.

3. A surge recorder of the electrostatic photosensitive type forelectrical apparatus, compris-I ing two concave dishes made ofelectrically nonconducting material disposed with their peripheriesabutting one another to provide a hollow shell, a film of electricallyconducting material on a face of each dish, the said films being spacedand insulated from one another, a partition of electricallynon-conducting material adapted to 6 f i divide the hollow shell at theabutting peripheriles, .agfilm of sensitized material on each face ofthepartition, a'rod-ty'pe electrode extending normally through one of thesaid dishes and having one end in contact with one ofthe films ofsensitized material, electrically conducting means to .secure .the otherend of the said electrode to the electrical apparatus in whicha surge tobe recorded passes, another rod-type electrode substantially inalignment with the first mentioned electrode and having one endextending through the other dish and in contact with the other nlm ofsensitized material at a point opposite the point of contact of thefirst mentioned electrode with a lm, the end in contact with a lm of atleast one of the electrodes being spring pressed, each of the electrodesbeing in electrical contact with the lm of conducting material on thedish through which it extends, an electrically conducting open endedhood connected to the first mentioned electrode at a point outside thehollow shell and extending around the said hollow shell and being spacedfrom the other electrode, the other end of the said other electrodebeing adapted to be coupled to ground.

4. A surge recorder of the electrostatic photosensitive type forelectrical apparatus, comprising two concave dishes made of electricallynonconducting material disposed with their peripheries abutting oneanother to provide a hollow shell, a partition of electricallynon-conducting material adapted to divide the hollow shell at theabutting peripheries, a film of sensitized material on each face of thepartition, a rod-type electrode extending normally through onel of thesaid dishes and having one end in contact with one of the films,electrically conducting means to secure the other end of the saidelectrode to the electrical apparatus in which a surge to be recordedpasses, another rod-type electrode substantially in alignment with thefirst mentioned electrode and having one end extending through the otherdish and in contact with the other lm at a point opposite the point ofcontact of the first mentioned electrode with a film, the end in contactwith a nlm of at least one of the electrodes being spring pressed, anelectrically conducting open ended hood connected to the rst mentionedelectrode at a point outside the hollow shell and being spaced from theother electrode and extending around the said hollow shell, the otherend of the said other electrode being adapted to be coupled to ground,and a resistor of the order of 20 to 100 megohms connected between thehood and the said other electrode.

5. A surge recorder of the electrostatic photosensitive type forelectrical apparatus, comprising two conducting members one of which isadapted to be connected to the electrical apparatus and one of which isa rod-type electrode, a non-conducting partition between the yconductingmembers, a film of sensitized material between the electrode and thepartition and engaged by the electrode, an electrostatic shield ofconducting material extending around and electrically connected to theconducting member which is adapted to be connected to the electricalapparatus and spaced from the other ccnducting member, and a resistor ofthe order of 20 to l0() megohms electrically connecting the twoconducting members.

JOHN HENRY WAGHORNE.

(References on following page) REFERENCES CITED ANumber v j Thefollowing references are of record in the 111e of this patent: 210911521UNITED STATES PATENTS 5 212611675 Number Name Date 2,269,225 1,526,770Brain Feb. 1T, 1925 2,377,622 1,649,180 Peters Nov. 15, 1927 2,463,125

8 Name Date Foust June 17, 1930 Tanberg May 12, 1931 Pattison Aug. 31,193'? Edler Nov. 4, 1941 Rich Jan. 6, 1942 Finzi June 5, 1945V SilverApr. 26, 1949

